1. Technical Field
The present disclosure generally relates to the field of transfer of thermal energy and, more particularly, to removal of thermal energy from a light-emitting device.
2. Description of the Related Art
Light-emitting devices, such as vertical-cavity surface-emitting lasers (VCSEL), light-emitting diodes (LED), laser diodes and the like, generate thermal energy, or heat, when in operation. The heat generated by a light-emitting device needs to be removed, or dissipated, from the light-emitting device in order to allow the light-emitting device to achieve optimum performance while keeping the light-emitting device within a safe operating temperature range. With the form factor of light-emitting devices and the applications they are implemented in becoming ever more compact, it is imperative to effectively dissipate the high-density heat generated in an area of small footprint to ensure the safe operation and optimum performance of light-emitting devices.
Many metal-based heat dissipation packages, whether water-cooled or air-cooled, have been developed for use in compact packages to dissipate heat generated by light-emitting devices. For instance, heat exchangers and heat pipes made of a material with high thermal conductivity, such as copper, copper-tungsten alloy, aluminum or iron, for example, are commercially available. However, most metal-based heat exchangers and heat pipes experience oxidation, corrosion and/or crystallization after long periods of operation. Such fouling factors significantly reduce the efficiency of heat transfer of metal-based cooling packages. Other problems associated with metal-based cooling packages include, for example, difficulty in precision alignment in mounting laser diode bars, VCSELs or LEDs or chips in laser diode/VCSEL/LED cooling applications, issues with overall compactness of the package, corrosion of the metallic material in water-cooled applications, difficulty in manufacturing, etc. Yet, increasing demand for higher power density in small form factor motivates the production of a compact cooling package with fewer or none of the aforementioned issues. Moreover, conventional packages typically use wire bonding to provide electrical power to the light-emitting device, but wire bonding may add cost and complexity in manufacturing and may be prone to defects in addition to occupying space unnecessarily.